Makovka



March 24, 1964 A. MAKovKA 3,126,010

CIGARETTE PAPER AND METHOD oF MAKING sAME Filed July 21. 1959 FIG. 1

FIG. 4

Tobacco Stalk Subdividing 2 Tobacco Leaf me 51mg Tobacco Stem or l y' @I Midrib of Tobacco l Leaf with Vein Digesiing j* Tobacco Root Washing Screening Cleaning o .d B f y Bleaching Washing u si e or o I Tobacco Stalk Cleaning Vascular Tissue i Region of v r 3 Tbacco Stalk Hydration i.- i- A Through Agitating Pith Portion or Cenral Part of Tobacco Stalk Thoroughly Mlxing of Fiber and Fibers Forming 3 Into Sheet Locaon of Basi Outside Bark of Tobacco Stalk Vascular Tis lue Region of Tobacco Stalk INVENTOR Alexander Ma kovko Plih Portion or Central Par of Tobacco Stalk United States Patent O 3,126,010 CIGARETTE PAPER AND METHD F MAKNG SAME Alexander Makovlra, Sea Cliff, NX., assigner to Wims Research Laboratories Inc., Sea Cliff, NSY., a corporation of New York Filed July 21, 1959, Ser. No. 828,448 2 Claims. (Si. 131-15) The present invention relates to a novel cigarette paper composed substantially of tobacco fibers derived from tobacco stalks, and more particularly to a novel method of making such cigarette paper.

This specification discloses an improvement over the disclosures of co-pending applications Serial No. 485,349, filed January 31, 1955, entitled Novel Cigarette Papers and Methods of Making Same, and now abandoned, and Serial No. 701,338, filed December 9, 1957, entitled Cigarette Paper Made with Tobacco Fibers Derived Entirely From the Tobacco Plant, and now abandoned.

Although tobacco materials such as tobacco leaves or artificially made tobacco sheets, known as reconstituted or homogenized tobacco sheets, made from particles of tobacco leaves, or tobacco waste material, such as crushed tobacco stems or heavy veins of leaves, tobacco dust, and the like tobacco products, have been used for many years for wrapping cigars and cigarettes, these tobacco products were substantially tobacco leaf material and could not provide the qualities, advantages, and characteristics necessary for a cigarette paper, among which are lightness in Weight, white color, thinness, strength, porosity, opaqueness, and ready combustibility.

In the attempts to utilize such wrappings, various treatments had been proposed for using various chemicals and for the crushing of such tobacco materials. However, irrespective of such treatments, a substantial number of prior art wrappings did not produce paper material per se which would be effective for making cigarettes either by automatic machinery or by hand. Furthermore, such processes usually necessitated the addition of other fibers and of binding materials.

It has been found that the stalks of tobacco plants provide the basic material surprisingly effective for cigarette papers if properly processed, and it is therefore the primary object of the present invention to provide a cigarette paper which is entirely derived from the tobacco plant, without the introduction of foreign fibrous material commonly used in the manufacture of cigarette paper, such as rag, flax, linen, hemp, flax straw and other products.

Another object of the present invention is the provision of a cigarette paper produced entirely from the tobacco stalk fibers which will be of proper weight and thickness and be of sufficient tensile strength to be readily adaptable for use in the formation of cigarettes, whether by hand, or conventional, automatic, high-speed machinery.

A further object of the present invention is the provision of a cigarette paper produced entirely from the tobacco stalk fibers which will possess the proper porosity and be sufficiently opaque and of low density so as to provide ideal combustibility to a cigarette made with such paper. A most important characteristic of the cigarette paper of the present invention is the extremely low density of the combustion gas, vapor, or smoke produced thereby, which gives the smoker a more satisfactory, mild, and purified tobacco taste. Furthermore, the desirable features of a paper made from tobacco fibers have been recognized in the prior art as set forth in Patent No. 1,016,844, granted February 6, 1912. Such more purified tobacco taste results from the fact, also, that the optical density of such gas, vapor, or smoke obtained as a result of the smoldering of paper made from the fibers of tobacco stalks and as measured by chromatographic tests, pres- ICC ently to be described, is substantially ten times weaker, and hence there is a more desirable combination of the gases, vapor or smoke from the cigarette paper with the gases, vapor or smoke from the tobacco making up the body of the cigarette.

Still further objects and advantages will appear in the more detailed description set forth below and as shown in the drawings, it being understood, however, that this more detailed description is given by way of illustration and explanation only and not by way of limitation, since various changes therein may be made by those skilled in the art without departing from the scope and spirit of the present invention.

In the accompanying drawings:

FIG. 1 illustrates the principal parts of the tobacco plant showing the part thereof which is utilized in accordance with the present invention;

FIG. 2 is a vertical cross-sectional View of the tobacco stalk taken on line 2-2 of FIG. 1;

FIG. 3 is a cross-sectional View taken on line 3 3 of FIG. 2; and

FIG. 4 is a block diagram showing the principal steps in the process according to the present invention.

The representations of the tobacco stalk in the above figures are to be regarded as diagrammatic.

It has been found that the fibers from the vascular tissue of the tobacco stalks are of exceptionally desirable length and strength and are of such fineness as to lend themselves effectively to the production of cigarette papers, and that these fibers effectively lend themselves in preparing, making and processing of the product, resulting in an unusually strong, yet lightweight and thin, tobacco fiber cigarette paper.

It would, of course, be desirable to remove a great deal of the marrow or pith material within the interior of the tobacco stalk, but the fibers from the vascular tissue of the middle portion of the tobacco stal-k are so effective as to strength, etc. that even though some marrow ingredients are left in the final paper, the desirable structure predominates and serves to give a most unusual and effective strength, durability and lightness to the cigarette paper.

In accomplishing the above objects, it has been found most satisfactory to derive the cigarette paper from tobacco materials and particularly from the stalks by alkaline treatments with which may also be combined bleaching treatments.

In the preferred procedures the stalks may be first subdivided, With or Without the pith, to form the base product. The most important ingredient to be obtained from the stalks and to be subsequently processed into the paper, is the middle portion, and external shell thereof. Further the external portion of the tobacco stalk gives a strong, fiber of unusual, desirable properties, which greatly enhance the quality and texture of cigarette paper. Although the vascular tissue fibrous material may be used alone, the marrow may be included.

Chromatographic tests by absorptive spectrometry as shown below, have indicated that the isolated neutral fraction of the non-soluble-in-water portion of total smoldering residue from the cigarette paper composed from tobacco stalk fibers, represents gases with up to 10 times lower optical density readings in comparison with the readings obtained under the same condition for the conventional cigarette paper from the other sources as flax, linen, rags, etc.

Cigarette paper as generally known in the art and the cigarette paper according to the present invention, were subjected to chromatographic tests by absorptive spectrometry substantially as follows:

Sampies of both cigarette papers were subjected to the process of smoldering, i.e. to burning or smoking without the presence of a flame, essentially simulating the conditions occurring in the human consumption of a cigarette. A controlled volume of air, in the present instance of liters of air per gram of paper consumed, was introduced upon the ignition of the specimens being tested at a temperature of 750 C., such temperature simulating the temperature attained by the conventionally smoked cigarette.

During the consumption of 200 grams, or approximately one-half pound of each sample, by smoldering, all volatile compounds liberated were individually collected and the natural hydrocarbon fraction separated therefrom was purified by means of adsorptive chromatography. The optical density of the adsorptive spectrum for the hydrocarbon fraction of each sample gave a reading of transmittance (i.e. of the degree of penetration of light through the gaseous or vapor compounds) as follows:

With respect to the gaseous compounds liberated from the residue of the conventional cigarette paper, the transmittance of light therethrough was within the range of 12.5% to 84%, whereas the transmittance of light with respect to paper according to the present invention was within the range of 79% to 100%, indicating the fact, as heretofore stated, that the optical density of the combustion gas and smoke resulting from smoldering of the cigarette paper according to the present invention is substantially ten times weaker than conventional cigarette paper.

In the present invention the cigarette paper is derived entirely from the tobacco stalks. The resulting product has the following characteristics:

Light weight of approximately 16 to 25 gram per square meter.

Tensile strength of 2-5 kg. measured on a strip of 30 mm. wide and 150 mm. long in conventionally tensile strength testing procedure.

Porosity -90 seconds, measured on a Grenier type porosity tested which indicates the time of passing of 50 cm.3 of air through the surface of 2 cm.2 of paper under the pressure of water column varying from 27 cm. at the beginning of the air passage to 14 cm. at the end of the air passage.

Opacity: 60-70 units measured with General Electric Photovolt Photoelectrical tester in conventional testing procedure.

Brightness: 75-85 units measured with General Electric Photovolt Photoelectrical tester in conventional testing procedure.

It has been found that tobacco stalk fibers of specific physical characteristics, for instance, or relatively short molecular-bound anhydroglucose units, of short, thin walled, and weak structure could not be processed with conventional methods of pulp preparation for cigarette papers, in which the most important step is the beating of pulp to a very high degree, which constitutes a fibrillatnig action of the longitudinal fibers and the transverse cutting of the fibers.

In conventional paper making, to achieve paper of substantial strength, the pulp must be beaten to a high degree. The degree of beating is what gives the pulp the property to retain water. It is measured by the freeness (Schopper-Riegler freeness) which is a measure of the capacity of drainage of a fibrous suspension, or more simply stated, the ability to release water. The greater the degree of beating of the pulp, the larger the surfaces are created by the cutting transversely of the fibers and the brillation thereof longitudinally, thereby providing more surface area and hence slowing the ow of water over the fibers. Beating, as effected in paper making, is actually the mechanical rupturing of the fibers. The beating ruptures the cell walls and exposes more inner fibrous fragments or fibrils. This exposure is due to the transverse cutting of the fibers and their fibrillation longitudinally. When the pulp is dried after the formation of the paper sheet, it develops tension, water evaporates therefrom, and the surfaces pull tightly together, making the paper sheet itself stronger. Since cigarette paper must not only be strong but also porous, it is conventional to use for the preparation of such cigarette paper, the strongest fibers available such as flax, linen, rags, etc. in which even the fibrils are strong. The pulp prepared from such materials is necessarily beaten to a very high degree to provide the extra surfaces necessary.

In contradistinction to this beating, in accordance with the present invention, the basic material, i.e. tobacco stalk fibers of the present process, require no beating action effecting any subdividing or transverse cutting of the fibers or the longitudinal fibrillation thereof. Such fibers are very short and Weak and the usual mechanical action of cutting and fibrillating need not be resorted to. The fibers, weakening under the chemical treatment in the digesting and bleaching processes, are mildly treated in such digesting and bleaching processes, just to a sufficient extent to attack the cell walls and thereby open small capillary pores in the fibers, rather than to effect a complete rupturing of such fibers. By simple agitating action, the water molecules are enabled to enter the capillary pores in the walls of the fibers and the water molecules thus become absorbed and retained within the fibers, becoming intimately associated with the inner fibrils of such fibers.

When the drying of the paper sheet is then effected, the water evaporates from the capillary walls of the fibers, thus yielding the necessary porosity which is particularly desirable in the ultimate cigarette paper. The evaporation of the water from between the fibers or contained in the capillary pores thereof, causes a sufficient degree of tension to make the fibers pull together and thus the paper becomes stronger.

The desirable strength and porosity of tobacco cigarette paper from tobacco stalk fibers is achieved according to the present invention, through the felting action of the tobacco stalk fibers of different length and other different physical properties in specific proportion. Primarily, instead of the conventional beating action, involving brushing, fibrillating, and cutting, the desirable degree of hydrolytic intimation is attained through the capillary action or incorporation of water molecules into the inner fibrilla of tobacco fibers, Without any physical subdivision, such as cutting and brillating of the tobacco stalk fibers.

By hydrolytic intimation is meant the capacity for water absorption and retention.

Tobacco stalk fibers can be classified, according to their physical characteristics, and the region in which they occur in the tobacco stalks, into four groups, in which the following proportions are found and are to be used in cigarette paper of the present invention:

65-70% of the fibers from the vascular tissue, of the middle portion of the tobacco stalks of .5 to 1.5 mm. lenth, 20-60 millimicrons width, and 5-10 millimicrons thickness.

10-15% of fibers of the Isame vascular tissue of the tobacco stalks, called vessel fibers or water transporting fibers, of isodiametrical nature, with serrated wall structure.

10-l5% of elementary tobacco stalk bast fibers from the outside bark of the stalks and from the region between vascular portion and the pith portion of the tobacco stalks, of 1.5-12 mm. length, 25-100 mill-imicrons width, and 5-25 millirnicrons thickness.

5-l0% of pith tobacco stalks fibers from the pith portion or central part of the stalk, of .01 to .5 mm. length, 40 to 320 millimicrons width, and 5-10 millimicrons thick.

The final product of the present invention is composed of the above described proportion of fibers, of specific physical characteristic and treated chemically and mechanically with consequently followed modified steps, and

will result in a tobacco-fiber cigarette paper of the de sired properties.

The combination of long and short, non-iibrillated or non-longitudinally cut and non-transversely cut fibers from the same sources such fibers being non-separated brils which build or make up the fibers along their longitudinal axis, is the dominant feature of the present invention.

In the product of the present invention, the tobacco stalk fibers remain in their natural physical form, shape and structure.

In extensive experimentation in attaining the objects of the present invention, it has been found that in the tobacco stalk, the ber binding material is quite different in quality from the usual binding material found in other pulp producing sources. It consists of lignified binding material to which is attached a high proportion of specitic tobacco pectic substance with the high percentage of hexuronic acid in their molecules.

It has been found desirable to eliminate or at least decrease the tobacco pectic substance from the tobacco stalks before the delignification step.

Further, it has been found that the step of unlocking the fibers from their binding pecto-lignin material in the digesting process of tobacco stalk, has to be carried out under specific conditions as to the amount of chemicals, temperature, time and pressure, in order to obtain the final product of desirable properties.

The proportion of chemicals in the hydrolytic cooking liquor is modified so that the chemical reaction of deligniiication leaves the fibers with the desirable properties.

In the preferred embodiment of this invention, the method of harvesting the stalks may be considerably varied. For example, the harvested or cut stalks with or without leaves may be pressed into bundles, bound and transported to the pulp plant, or they may be cut after a leaf crop has been harvested, or they may be permitted to stand in the fields for considerable periods of time. As an alternative, the stalks may be collected, with or without stripping the leaves, and such stalks may be dried and bound in bales and shipped to the pulp making facility.

It is preferred to cut the stalks or to harvest the stalks from the roots four to six months after the crop of leaves has been harvested. It has been found particularly satisfactory to leave the stalks in the field for the winter season and for at least a month or longer in cold weather. It has been found that the longer the stalks stand in the field, the lighter the paper will be in color and the less bleaching action required. It has been found that the most effective result is achieved by exposing tobacco stalks to natural or artificial action of ultraviolet rays. In case the natural action of the sun is used, it has been found that tobacco stalk should be harvested at least 90 days, but preferably 180 days after the harvesting of tobacco leaves is accomplished. With the above treatment the amount of pith will be decreased. The presence of such pith in the final product is undesirable in an amount more than to 10% of the entire fiber content as described above.

The tobacco stalks will either be of the flue-cured type or of other types which are harvested in different ways. For example, with the flue-curved type, the stalks are cut above the soil at a distance of 1" to 2" in sun dried condition.

According to other types of harvesting, the stalks and the leaves are harvested and then the leaves are removed from the harvested stalks after curing and then the stalks are available for making the pulp.

It has been found quite effective in obtaining the best grade of cigarette paper that the stalks be field-dried, that is, drying by the action of the sun, to a moisture content of below Although the stalks may be cut and dried in various 6 types of mechanical drying equipment, it has been found that superior paper will result from sun-dried products which have been left in their original condition until the desired moisture content has been obtained without removal from the fields.

The stalks are then baled in baling machines for handy transportation and are kept dry.

As an alternative to the baling, the stalks are chipped or cut in small pieces immediately, in a chipping machine, to about 1/2 to 5 lengths for convenient packing into a digester and obtaining better cooking results.

The best chips are those which are 1" to 2 in length.

It has been found that after the tobacco stalks have been chipped or sub-divided, they are most desirably cooked, or digested, at an elevated temperature at a pressure above atomspheric, according to any well known digesting method as sulphate, kraft, soda, neutral sulphite semi-chemical, or sulphite, modified for digesting of tobacco stalks under super atmospheric pressure of 5-10 atmospheres, at temperatures of 12S-180 C. for 1 to 3 hours, and cooking liquor-to-stalks ratio of 2:1, to 8:1, whereby the desirable quality of tobacco stalk ber cigarette paper will be obtained.

In such digesting processes, however, any of the following procedures is preferable:

(a) 1600 kg. tobacco stalks with 15% of moisture content are placed in rotary digester in the form of chips 1/2 to 2 inches in length.

The composition of 316 kg. sodium hydroxide (NaOH) 89 kg. sodium sulphide (NazS) kg. sodium carbonate (Na2CO3) is mixed and placed in digester with 5400 liters of filtered cold water.

Digester is heated to about 90 C. with valve open for one minute to allow escape of gases, heated to 170 C. and cooked for one hour and 55 minutes, washed, screened, cleaned, and bleached.

(b) The same amount of tobacco stalks are used as in (a) above. The composition of 270 kg. sodium hydroxide 75 kg. sodium sulphide 60 kg. sodium carbonate is mixed and placed in digester with 5400 liters of filtered cold water. Digester is heated to about 90 C. then valve opened for 1 minute to allow escape of gases, heated to 168 C. and the load is cooked for 2 hours, 25 minutes, then washed, screened, cleaned, and bleached.

(c) Tobacco stalks (chips) are placed in stationary vertical digester connected with cooking liquor circulating system. The composition of chemicals: for every kg. of tobacco stalks (dry weight) is 2l kg. sodium hydroxide 5.8 kg. sodium sulphide 6.6 kg. sodium carbonate The above mixture is mixed in 500 liters of ltered water for use as the circulating liquor. The circulating liquor is heated to about 90-95 C. and the valve is opened to allow the escape of gases. The heating of the cooking liquor is continued to 168 C. and cooked for 2 hours and 50 minutes.

The pulp which results after any of these digesting operations may be more finely divided by mechanical operations, i.e. washed, cleaned, screened, and conventionally bleached to obtain purified tobacco fibrous pulp.

As a result of these processes there will be produced a fibrous pulp which will contain about 20 to 50% of the original tobacco stalks.

The pulp material which is thus obtained will have the fiber content in proportion of long, medium, and short fibers as described above, which will give enhanced strength and with these long fibers will be interlaced and intermilled a large number of medium fibers ranging from 0.5 to 1.5 millimeters in length, which will give a most effective type of tobacco cigarette paper which will have desirable coating and strength characteristics.

In preparing the pulp for making the paper concentration mass, the pulp is cleaned, washed, and screened after bleaching. After the bleaching has been completed, the pulp or paper mass should be prepared through cleaning and relining equipment such as a hydrocyclon cleaning system where the tobacco pulp is cleaned at least two times. The first time the cleaning is carried out at a lower pressure of 2 to 3 atmospheres and at a higher concentration of 0.5% of the pulp based upon the total weight of the aqueous slurry, and the second cleaning operation is carried out at a higher pressure of 3 to 4 atmos` pheres with a lower concentration of 0.3 to 0.4 percent of fibers based upon the total weight of the aqueous slurry. The pulp is then placed in any suitable tank or agitating machine for agitating of pulp in high consistency of to 25% pulp in water suspension to achieve the last step of tobacco-stalk-ber pulp preparation just before putting on the paper machine for sheet formation. This step comprises the expedient which consists of an extremely slow movement (2 to 10 rotations of the pulp mass in 1 hour) of bers in water suspension in high consistency of 10 to 26% of bers based on dry weight of the fibers, at elevated temperature of 35 to 40 C. for 10 to hours. The agitation and movement of the mass is caused by the rotating action of the agitator at a desirable speed so as to cause the high consistency pulp mass to move from 2 to 10 rotations per hour. The conventional beater apparatus, modified as hereinafter indicated, may be used for this action. In this case the beaters are used as agitating tanks only. The knives which cause beating action of brushing, cutting and fibrillating should be eliminated. The rotating drum which also has knives, should be elevated completely so that no contact will exist between bottom knife and the knife on the rotary drum. The drum is used as agitating means only.

The pulp or paper material which has been prepared throughout the agitating machine, cleaning equipment and reiner will then be directed to the paper-making machine. The screen is adjusted at such a rate and at such a depth and speed of 35 to 60 meters per minute, as to give the necessary thickness after the fibers have been matted together and have been settled and the water has been removed.

The screen belt will direct the tobacco stalk bers containing both the long and short fibers through the felt belt to a drying cylinder, which consists of one or more large drying drums.

Now the pulp is formed into a matted sheet by passing onto a Fourdrinier paper machine. Although the conditions on the Fourdrinier machine may be varied it has been found desirable to use a speed of about 35 to 55 meters per minute with adjustments to receive a paper of 16 to 25 grams per square meter.

It is desirable just before directing the pulp into the Fourdrinier paper machine, to pass the pulp through a Jordan rening machine or conical reliner, such as is known in the trade as Ions reliner. It is particularly important to adjust the Ions rener so that it does not cause any cutting and librillating of bers. It is also so adjusted as to have the maximum opening possible between the outside and inside conical shells and the knives.

The function of such adjusted rener is to perform thoroughly mixing of bers with carbonate added and to eliminate knots, clumps or spiral bers. This is important since such refiners are conventionally used to complete the action of cutting and shortening of fibers.

From the drying cylinder the paper is taken and rolled for further processing and utilizing in making cigarettes.

The last stage after this rolling will be to cut the cigarette paper in proper length and widths so that it may be put in automatic machinery. Or, it may be cut in rolls for automatic cigarette paper making machinery or cut in separate sections for hand cigarette manufacturing procedures. Also calendering, water-marking, as Well as saturation with ilavoring extracts may be carried out, or coating with harmless aqueous solution of salts or organic .acids in order to increase combustibility as Well as the brightness of ash of cigarette paper.

It is possible to add magnesium carbonate and calcium -carbonate and titanium dioxide to enhance the opacity and combustibility. Calcium carbonate may be used in an amount from 5 to 45% and magnesium carbonate and titanium dioxide in amount of 1 to 10% each, with a resultant loss of approximately 75 to 85% of such additives in the final product, which loss is due to washolfs in sheet formations.

The carbonates and titanium dioxide should be screened before use so that they pass through a 150 mesh screen. Both these materials are preferably included in desired amounts and proportions and thoroughly mixed with the pulp, just before being directed to the paper making machine. However, they are desirably not used where high strength paper is desired, since they do somewhat decrease the strength.

Desirably, the tobacco liber cigarette paper should be prepared so that it will weigh about 10 to 40 grams per square meter.

The resulting 100% tobacco ber cigarette paper according to the present invention is characterized by a tensile strength of between 2 and 5 kg. measured with respect to strips 30 millimeters in width, and 150 millimeters in length, an ash content of 7 to 20% with a white color; a weight of 16 to 25 grams per square meter; a thickness of about 0.033 to 0.035 millimeter; an opacity and brightness of 60 to 85 units measured with conventional photovolt photoelectric tester; and an elongation of 1 to 3% in long direction and 1 to 2% in transverse direction.

While there has been herein described a preferred form of the invention, it should be understood that the same may be altered in details and in relative arrangements of parts within the scope of the appended claims.

It should be further noted that the paper of the present invention, although directed for use in automatic machinery for cigarette production, may be equally well applied to hand made cigarettes or as paper used by the consumer for making cigarettes from cut, Hake, or granulated tobacco.

I claim:

1. The process of making a cigarette paper whose fiber content consists exclusively of tobacco stalk fibers, comprising the steps of eld drying the stalks from to 180 days before harvesting the stalks, next digesting the stalks, at an elevated temperature for 1 to 3 hours under pressure above the atmosphere in a cooking liquor consisting of 12 to 23 kg. of sodium hydroxide, 5 to 12 kg. of sodium sulphide, 4 to l0 kg. of sodium carbonate, for every 100 kg. of stalks in a ratio of said cooking liquor to stalk within the range of 2:1 to 8:1; resulting in a pulp, followed by washing, screening and cleaning of said pulp; followed by the step of bleaching said pulp; wherein the resulting pulp fiber has a content within the range to 20 to 50% of said original tobacco stalk; then cleaning, washing and screening said pulp; followed by agitation of said pulp; said fibers being in their original lengths and transverse structure and whose structural integrityV is substantially preserved; then passing said pulp through a refining machine for thorough mixing of said bers without substantially cutting or ibrillating thereof; and then forming said pulp into matted sheets.

2. A cigarette paper made by the process defined in Claim 1. 2,338

4,302 References Cited 1n the le of this patent 759 UNITED STATES PATENTS 5 20,395

346,887 Bennett Aug. 10, 1886 999,986 Giordano Aug. 8, 1911 1,016,844 Moonelis Feb. 6, 1912 1,903,942 Reichard Apr. 18, 1933 2,673,565 schuf Mar. 30, 1954 10 N.Y.

10 FOREIGN PATENTS Great Britain 1854 Great Britain 1876 Great Britain 1887 Great Britain 1911 OTHER REFERENCES Condensed Chemical Dictionary, pages 663 and 664, published 1950 by Reinhold Publishing Co., New York, 

1. THE PROCESS OF MAKING A CIGARETTE PAPER WHOSE FIBER CONTENT CONSISTS EXCLUSIVELY OF TOBACCO STALK FIBERS, COMPRISING THE STEPS OF FIELD DRYING THE STALKS FROM 90 TO 180 DAYS BEFORE HARVESTING THE STALKS, NEXT DIGESTING THE STALKS, AT AN ELEVATED TEMPERATURE FOR 1 TO 3 HOURS UNDER PRESSURE ABOVE THE ATMOSPHERE INA COOKING LIQUOR CONSISTING OF 12 TO 23 KG. OF SODIUM HYDROXIDE, 5 TO 12 KG. OF SODIUM SULPHIDE, 4 TO 10 KG. OF SODIUM CARBONATE, FOR EVERY 100 KG. OF STALKS IN A RATIO OF SAID COOKING LIQUOR TO STALK WITHIN THE RNGE OF 2:1 TO 8:1; RESULTING IN A PULP, FOLLOWED BY WASHING, SCREENING AND CLEANING OF SAID PULP; FOLLOWED BY THE STEP OF BLEACHING SAID PULP; WHEREIN THE RESULTING PULP FIBER HAS A CONTENT WITHIN THE RANGE TO 20 TO 50% OF SAID ORIGINAL TOBACCO STALK; THEN CLEANING, WASHING AND SCREENING SAID DPUOP; FOLLOWED BY AGITATION OF SAID PULP; SAID FIBERS BEING IN THEIR ORIGINAL LENGTHS AND TRANSVERSE STRUCTURE AND WHOSE STRUCTURAL INTEGRITY IS SUBSTANTIALLY PRESERVED; THEN PASSING SAID PULP THROUGH A REFINING MACHINE FOR THOROUGH MIXING OF SAID FIBERS WITHOUT SUBSTANTIALLY CUTTING OR FIBRILLATING THEREOF; AND THEN FORMING SAID PULP INTO MATTED SHEETS. 